Objective: The purpose of this report is to present the diagnosis of familial amyloid polyneuropathy (FAP) based on vitreous biopsy and to demonstrate immunohistochemical images of transthyretin amyloid protein from vitreous samples.
Design: Retrospective case series.
Methods: Retrospective review of clinical charts of patients with FAP who underwent vitrectomy for vitreous opacities and had immunostaining performed on the vitreous specimens.
Participants: Three patients were selected for the study: 2 patients had already been diagnosed with FAP, and in 1 of the patients the vitreous sample served to establish the diagnosis of FAP.
Results: Pathology examination of the vitreous specimens confirmed the presence of amyloid with positive Congo red staining, and transthyretin was identified with immunolabeling techniques. In this report, we present immunohistochemical staining images of transthyretin deposits in the vitreous tissues.
Conclusions: Transthyretin amyloidosis is usually confirmed with positive Congo red staining for amyloid identified by biopsy of peripheral nerves, salivary glands, or abdominal fat. Ocular manifestation of FAP typically appears years after the onset of the disease, and therefore eye tissue specimens usually are not subject to diagnostic biopsies or transthyretin identification. However, in patients with negative systemic tissue biopsies or early ocular involvement, transthyretin identification from samples obtained during vitrectomy may be useful in establishing the diagnosis, and we present the first immunohistochemical images of transthyretin amyloid of vitreous origin, which confirm the elevated deposition of the altered protein in ocular tissues in FAP.
Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.